The present invention generally relates to intravascular balloon catheters. More specifically, the present invention relates to intravascular balloon catheters for the delivery of embolic devices and agents to aneurysms.
Embolic devices and agents have been proposed for the treatment of vascular diseases and malformations requiring the formation of thrombus. For example, embolic coils have been proposed for the treatment of aneurysms. A currently preferred method of deploying an embolic coil to an aneurysm utilizes an electrolytically detachable guide wire tip or coil commercially available under the trade name GDC (Guglielmi Detachable Coil) available from Boston Scientific Corporation. The GDC system and method of use is substantially described in U.S. Pat. No. 5,354,295 to Guglielmi et al., and other related patents and patent applications.
Some types of vascular aneurysms have a relatively large opening between the native vascular lumen and the cavity of the aneurysm. For example, aneurysms which have an opening that is the same size or larger than the cavity may be referred to as wide-neck aneurysms. Wide-neck aneurysms are typically difficult to embolize with embolic devices and agents because the embolic material has a tendency to fall out or otherwise exit the aneurysm during delivery. In the case of embolic coils, wide-neck aneurysms are particularly problematic when the neck of the aneurysm is as large or larger than the expanded size of the embolic coil.
To address this problem, a separate balloon catheter is often utilized to block the neck of the aneurysm during embolic coil delivery to prevent the coil from exiting or protruding out of the aneurysm. Although not intended for use in the treatment of wideneck aneurisms, U.S. Pat. No. 5,795,331 to Craigg et al., disclose a method and apparatus for delivering an occluding agent into an aneurysm or branch vessel utilizing a balloon catheter. The balloon catheter disclosed by Craigg et al., includes an elongate shaft having a guide wire lumen and one or more delivery lumens for the delivery of an embolic agent. A balloon is disposed about the distal end of the elongate shaft for inflation in the vessel adjacent the aneurysm such that the exit port of the delivery lumen is disposed adjacent to the opening of the aneurysm. In each of the embodiments disclosed by Craigg et al., the portion of the elongate shaft which defines the delivery lumen extends distal of the balloon thereby unnecessarily adding stiffness to the distal end of the catheter and compromising flexibility and navigability thereof. In addition, all of the embodiments disclosed by Craigg et al. utilize delivery lumens which are separate from the guide wire lumen thereby unnecessarily increasing the overall profile of the catheter in situations where the some of the lumens may be combined.
To address these problems, the present invention provides improved intravascular balloon catheters for the delivery of embolic devices and agents to wide-neck aneurysms. In one embodiment, the present invention provides a balloon catheter having a combined guide wire/delivery lumen and a lateral delivery hole for an embolic device to pass from the combined lumen into the wide-neck aneurysm. The combined lumen reduces the profile of the balloon catheter to provide improved trackability, particularly in small diameter tortuous vasculature. The balloon may comprise a multi-lobed design with the delivery hole disposed between adjacent balloon lobes. The balloon catheter preferably includes a diversion member disposed in the combined lumen to cause the embolic device to divert from the combined lumen, through the delivery hole, and into the opening of the wide-neck aneurysm.
In another embodiment, the present invention provides a balloon catheter including a shaft having a shaft tube and a co-extending delivery tube. The delivery tube includes a distal opening for the delivery of an embolic agent or device such as a coil. The delivery tube terminates proximal of the distal end of the shaft tube for added flexibility and improved trackability. An inflatable balloon is connected to the distal end of the shaft, and the balloon may inflate eccentrically about the distal end thereof. The eccentric balloon pushes the distal opening of the delivery lumen adjacent the opening of the wide-neck aneurysm. The balloon catheter may include a distal guide wire seal to accommodate a single lumen design.